Plasma displays have been known since the late 1960's. A plasma display encloses a gas or mixture of gases between crossed and spaced conductors. The crossed conductors define a matrix of cross over points, arranged as an array of miniature picture elements (pixels) or lamps which provide light. At any given pixel, the crossed and spaced conductors function as opposed plates of a capacitor, with the gas serving as the dielectric. When a sufficiently large voltage is applied, the gas at the pixel breaks down into a plasma of electrons and ions which glow as the electrons and ions in the plasma combine in the local region of that pixel. The discharge, if not within the visible spectrum (e.g., ultraviolet light), may be converted to visible light by use of phosphors.
The voltage required to illuminate a given pixel is governed by Paschen's Law. Under Paschen's Law, the voltage at which a gas breaks down into a plasma, the so-called spark or firing voltage, is related to the product of the pressure of the gas, p (in mm Hg), times the distance d (in cm), between the electrodes. By scanning the conductors (for example sequentially) with a voltage sufficient to cause the pixels to illuminate, and repeating the process at least 60 times per second, a steady image can be perceived by the human eye.
Plasma displays are typically large scale devices. Conventional miniature displays are manufactured using liquid crystal display (LCD) technology. LCD's have been successfully fabricated at high pixel densities but, unlike plasma displays, the LCD pixels themselves are not self-illuminating. Instead, LCD displays require auxiliary lighting from behind to illuminate the pixels. Furthermore, it is difficult to fabricate LCD displays on a transparent substrate that permits back lighting. Thus, conventional high-resolution miniature LCD arrays are first fabricated on one substrate and then the entire LCD array structure is "transferred" from to a second transparent substrate. A separate back light must also be provided, along with an external interface to connect the miniature LCD array to the control circuitry. Further, an LCD display requires a separate driver for each pixel. This increases the area each pixel requires on the substrate and thus reduces the maximum pixel density.
The present invention solves problems in the art by providing a self-illuminated miniature high-resolution plasma display that can be integrated and operated on a single semiconductor substrate using conventional semiconductor fabrication techniques.